I'm working on a project. Using a 12V adapter to power both a Arduino Nano and a 12V LED strip. I would like to ask which of the following power supply methods (to Nano) is the best:
Using a 9V buck converter. Input 9V to Nano VIN pin.
Using a 5V buck converter. Input 5V to Nano 5V pin.
Don't use buck converter. Directly input 12V to Nano VIN pin.
It is also worth mentioning that there is also a Pro Micro next to the Nano. Pro Micro and Nano share GND and have some other pins connected. The Pro Micro will picks up Analog signals. I'm not sure if the Buck converter will make big noise to the Analog Pin. Please give me your advice. Thank you!!!
I measured the output of the adapter using a multimeter. It is 12.xx V. I read earlier that some people said that the temperature of Nano‘s LDO at 12V may slowly rise, resulting in abnormal work.
You can look up the LDO on the nano to find its datasheet. That will in turn allow you to calculate the temperature rise. The datasheet should give information about what temperature rise is acceptable.
The answer probably depends on how much current you're drawing for your project. As long as you aren't powering anything from the Nano's regulated outputs, the current should be pretty low and your temperature rise should be minimal.
@ay16888 Which is why you are asked to provide a project schematic. Otherwise, the answer can only ever be "well, it depends...". If you're powering 15 20 mA LEDs, or 300 mA of other devices for example, then you're working the LDO very hard, and every watt you can avoid dissipating at the LDO is valuable. If you're doing nothing but scanning buttons, it's all good.
I use a 12vdc power supply with a 1000uF electrolytic capacitor across power and ground, and 500 ohms resistance on the signal pin between a Nano and strip of 300 WS2811. Two years. No heat. No failures.
Thanks for your suggestion. I don't really use the Nano to power anything. But I think it may not be easy to calculate the temperature, because the heat dissipation may not be easy to evaluate. I might test the temperature in an experimental way.
Then 12V input will be okay for the Arduino's regulator, though it may be warm to touch. Just remember, if you later add any significant load to the 5V pin(for example, an LCD display), or to multiple digital outputs on the Arduino, you are increasing the heat dissipated by the LDO.
The other consideration to be mindful of is ambient conditions - encasing that Arduino in an insulated box, where the heat cannot escape, results in far different conditions than leaving it lying on the bench, where heat is easily radiated to the environment.
Adding some information about my follow-up experiments. 12V was directly input into Nano's VIN pin. After running 30min, I felt no heat on LDO (using my finger). The LDO's temperature even lower than the LED strip...
But I accidentally broke two Nano. The first is when measuring the LDO temperature with a thermocouple. The LDO directly smokes and burns a bubble (maybe)...The second is that I inserted the Nano into the bus misaligned. The MCU smoke up...
Only way I can imagine destroying a reg with a thermocouple is by shorting pins, not knowing the thermocouple is metal and thus you shouldn't touch the pins, only the body of the reg.
In the second case I will replace the word "bus" with shield, and yeah, plugging a nano into the wrong pins of a shield will make smoke, either when you subsequently power it, or immediately, if you've not yet learned not to plug/unplug stuff that is powered. Consider that a cheap lesson learned, and don't do it again.
I want to test whether the LDO temperature will be too high in this case. As camsysca said, burning up might caused by shorting pins. For the second case, may be I should used the phrase 'Female Header'. May be 12V voltage putting into Nano's GND caused IC burning up i think.
